Nucleophilic substitution reactions are frequently performed as an experiment in undergraduate organic chemistry courses. Reactions taking place at saturated carbons are mainly classified as SN1 or SN2, where S stands for substitution, N for nucleophilic, and the number indicates the molecularity of the reaction (1 for a unimolecular process, 2 for a bimolecular process). In the SN2 reaction the attack of the nucleophile and elimination of the leaving group occur simultaneously in a concerted process and its rate is proportional to the concentration of both the alkyl halide and the nucleophile.